When Tsunade and Jiraiya arrived at the Leaf Village Shinobi Hospital, they didn't slow their pace.
They bypassed the main corridors, ignored the startled nurses, and eventually reached a narrow stone stairwell reserved for senior medical staff and those with clearance from the Hokage. The air cooled as they descended deeper and deeper.
The archives door groaned when Tsunade pushed it open.
Inside, rows of shelves stretched into shadow. Weathered scrolls bearing the various clan crests, such as the Senju and more, sat beside sealed Uzumaki records salvaged from the ruins of Uzushiogakure. Anatomical charts lined one wall—faded parchment depicting chakra pathways in meticulous, almost obsessive detail.
At this hour, the room was empty of life.
"Well, princess," Jiraiya said lightly, his usual playful tilt returning, "where do we start?"
Tsunade didn't answer.
She moved along the shelves at a pace that made the dust stir in her wake, scanning labels as she passed. Senju cellular studies. Early chakra pathology reports. Experimental reinforcement theories deemed "too dangerous" by the village leadership.
Only then did she finally turn to Jiraiya, utterly focused on the task at hand.
"Don't just stand there," she said, already turning back to the table. "I need Senju cellular studies separated from general anatomy, Uzumaki vitality and chakra records in their own stack, and anything referencing coil rupture or regenerative tissue pulled aside."
A brief pause.
"Organise it chronologically where possible," she continued. "If it contradicts itself, flag it. Oh, and try not to misplace anything. Some of this is older than even you."
Within minutes, scrolls lay unrolled across a long wooden table, ink diagrams layered over older anatomical sketches. Some were decades old. Others, older still.
Candlelight flickered against the stone walls, casting moving shadows across spiralled coil diagrams and branching tenketsu maps.
Tsunade sat at the centre of it all, brush in hand, already writing corrections in the margins.
Only when the scratching of ink stopped hours later did she finally lean back, arms crossing tightly over her chest.
Across from her, Jiraiya watched in uncharacteristic silence.
Tsunade exhaled once through her nose.
"Listen carefully, Jiraiya. Kazane's chakra system isn't unstable; it's overloaded."
Her finger tapped against a sketched diagram of Kazane's chakra coils—dense spirals layered atop each other far beyond what an infant should possess.
"What we are dealing with is, firstly, her chakra coils are under constant strain.
Second, the nervous system is getting overstimulated.
Third, the body is having to repair itself faster than it should."
Jiraiya's brows lowered. "Healing too fast is a problem?"
"When it's a constant cycle like this, "Tsunade said. "Then yes, Jiraiya, it's a problem."
She pushed the scroll toward him.
"I'm not going to suppress her chakra. That would cripple her. I'm going to stabilise it and teach it where to go, " she informed him. "That should buy her time."
"Should buy her time?" Jiraiya stared at her. "I thought you were treating her, not just prolonging her death."
"I am Jiraiya, but this is a race against time, " she hurried to say. "The main problems right now are the internal pressure, neural feedback and micro-tearing"
She stood and began pacing, arms still crossed.
"Compression inflammation. Think hypertension, but inside the chakra network."
Jiraiya's gaze hardened.
"The pressure builds up, irritates the coils, and inflames nerves. That's the burning fever. The shallow breathing. Eventually, it becomes migraines. Chest tightness. Limb tremors."
She glanced back at him.
"She'll need to vent it."
"She?" He asked. "Not you"
"Yes, not I but Kazane herself."
"How?" he asked quietly.
"Controlled release through the tenketsu. Measured pressure cycling. Like teaching someone how to breathe properly after years of suffocating."
She tapped two fingers against her own sternum as she demonstrated the necessary rhythm, one Kushina and Minato had already begun using instinctively.
"I'll use precise regenerative pulses to calm irritated pathways — but not too much. Over-heal a coil, and it will thicken, becoming a new problem."
"What about the, eh, neural feedback, was it?" asked Jiraiya.
"This," Tsunade said, her voice dropping, "is the part that concerns me."
She rolled out another diagram—this one mapping chakra flow around the brain.
"Her emotions spike, chakra follows, flooding the brain. Causing pain, which causes more emotion, creating another chakra spike."
Jiraiya swore under his breath. "A feedback loop." The true horror of the situation was only now dawning on him.
"I've seen what trauma does to chakra control," Tsunade replied, eyes distant for half a second too long. "I'm not letting that happen to an infant."
"So?"
"So we regulate," she said, listing off treatment methods.
"Meditation cycles. Breathing drills. Grounding exercises disguised as play."
Her gaze flicked toward him.
"I'll have Shizune help with that."
"And if that's not enough?" Jiraiya asked.
Silience.
"It will have to be."
"Then there is the micro-tearing."
Tsunade unrolled a third scroll, this one more clinical.
"If her coils are overstretching, that's fatal territory."
Jiraiya straightened.
"Large volumes of chakra will shred the system over time."
Her finger traced thin fractures along the illustrated network.
"I'll reinforce damaged threads with precision cellular knitting. Small regenerative pulses, spaced properly." Tsunade continued. "It's like healing a tendon. Too much repair makes it rigid. Too little and it snaps."
She met his eyes.
"Once she is older and starts learning Jutsu, I'll set a hard output threshold, along with mandatory recovery periods."
"If she ignores it when she's older?" He asked.
A pause. Her gaze turned icy.
"I'll break her legs before she breaks her coils."
Jiraiya believed her.
"And that rhythmic pulsing she's doing instinctively?"
Jiraiya thought of the description Minato had given.
"Good, she's already venting her chakra ", Tsunade said. "That must be survival instinct kicking in."
Her eyes hardened with resolve.
"I'll refine it so it releases without rattling her entire system."
"This next part annoys me."
Jiraiya smirked faintly. "Oh, what part is that?"
"She's already experiencing constant discomfort," Tsunade said sharply. "That means she'll get used to pain early. Learn to hide it."
The humour vanished.
"So regular internal scans and healing sessions are a must."
She paused, then spoke more quietly.
"Frankly, the only reason she isnt already dead is that she's inherited the Uzumaki bloodline."
Tsunade gave him a look.
"That regenerative vital strength is the only reason her system hasn't collapsed already."
She let that sink in.
"But healing fast isn't immortality."
Her voice was firm, clinical.
"It just buys time."
Final Verdict
Tsunade rolled up the final scroll and tied it closed.
"This isn't a curse, " he whispered. "Handled properly. She will grow to be terrifying."
"Mishandled?" Jiriaya couldnt help but ask.
Her eyes lifted to his.
"Complete collapse of her chakra pathway before adulthood."
Jiraiya folded his arms slowly.
A beat.
The candles flickered.
And for the first time since arriving back in the village, Jiraiya understood the weight behind her decision to stay.